The invention relates to the field of intraluminal catheters, and particularly to guiding catheters suitable for intravascular procedures such as angioplasty, stent deployment, pacing lead deployment and the like.
In percutaneous transluminal coronary angioplasty (PTCA) procedures, a guiding catheter having a shaped distal section is percutaneously introduced into a patient's vasculature and then advanced through the patient's vasculature until the shaped distal section of the guiding catheter is adjacent to the ostium of a desired coronary artery. The proximal end of the guiding catheter, which extends out of the patient, is torqued to rotate the shaped distal section and, as the distal section rotates, it is guided into the desired coronary ostium. The distal section of the guiding catheter is shaped so as to engage a surface of the ascending aorta and thereby seat the distal end of the guiding catheter in the desired coronary ostium and to hold the catheter in that position during the procedures when other intravascular devices such guide wires and balloon catheters are being advanced through the inner lumen of the guiding catheter.
In the typical PTCA or stent delivery procedures, the balloon catheter with a guide wire disposed within an inner lumen of the balloon catheter is advanced within the inner lumen of the guiding catheter which has been appropriately positioned with its distal tip seated within the desired coronary ostium. The guide wire is first advanced out of the distal end of the guiding catheter into the patient's coronary artery until the distal end of the guide wire crosses a lesion to be dilated or an arterial location where a stent is to be deployed. A balloon catheter is advanced into the patient's coronary anatomy over the previously introduced guide wire until the balloon on the distal portion of the balloon catheter is properly positioned across the lesion. Once properly positioned, the balloon is inflated with inflation fluid one or more times to a predetermined size so that, in the case of the PTCA procedure, the stenosis is compressed against the arterial wall and the wall expanded to open up the vascular passageway. In the case of stent deployment, the balloon is inflated to plastically expand the stent within the stenotic region where it remains in the expanded condition. Generally, the inflated diameter of the balloon is approximately the same diameter as the native diameter of the body lumen being dilated so as to complete the dilatation or stent deployment but not overexpand the artery wall. After the balloon is finally deflated, blood flow resumes through the dilated artery and the dilatation catheter and the guide wire can be removed therefrom. Generally, the stent deployment may be accomplished simultaneously with or after a PTCA procedure has been performed at the stenotic site.
In addition to their use in PTCA and stent delivery procedures, guiding catheters are used to advance a variety of electrophysiology-type catheters and other therapeutic and diagnostic devices into the coronary arteries, the coronary sinus, the heart chambers, neurological and other intracorporeal locations for sensing, pacing, ablation, and other procedures. For example, one particularly attractive procedure for treating patients with congestive heart failure (CHF) involves introduction of a pacing lead into the patient's coronary sinus and advancing the lead through the patient's great coronary vein and a branch of the great coronary vein until the distal end of the pacing lead is disposed at a location which allows the electrical impulses from the pacing lead to pace the left ventricle of the patient's heart. A second pacing lead may be disposed within the patient's right ventricle or a cardiac vein draining the patient's right ventricle and both the left and right ventricle may then be paced by the pacing leads, resulting in greater pumping efficiencies and greater blood flow out of the heart which minimizes the effects of CHF.
Commercially available guiding catheters are typically constructed of a lubricious, polymeric inner liner, a polymeric outer jacket, and a reinforcing structure disposed between the inner liner and outer jacket formed of woven, braided, or wound strands which are usually metallic, high strength polymers or combinations thereof. The lubricious inner liner serves to diminish the frictional forces generated from the passage of interventional devices within the inner lumen. The lubricious inner liner is commonly formed of polytetrafluoroethylene (PTFE) because of its low coefficient of friction.
The conventional PTFE inner liner is relatively thin. Further reduction in its wall thickness is difficult, because the PTFE liner would lack the physical integrity to withstand the caustic chemical etching typically used to bond it to other catheter components.
On the other hand, clinical requirements for utilizing guiding catheters to advance catheters and other intravascular devices have resulted in a need for increased transverse dimensions of the inner lumens of guiding catheters to accommodate a greater variety of large intracorporeal devices with little or no increase in the outer transverse dimensions of the guiding catheter to present a low profile which facilitates advancement within the patient's body lumens and openings. These catheter design changes have required a reduction in total wall thickness, including a reduction in the thickness of the inner liner. It would thus be desirable to provide a thinner inner liner to maximize the inner lumen diameter. Alternatively, a reduction in the thickness of the inner liner would permit a reduction in the outer transverse dimensions of the catheter to ease passage through narrow, tortuous blood vessels or an increase in the thickness of the other catheter layers for greater strength without increasing the outer profile. A suitable thinner inner liner should still provide the requisite physical and mechanical properties for its use, such as lubricity, flexibility, and sufficient strength and integrity. In addition, it would be desirable if the inner liner material had physical characteristics which would not be compromised by radiation sterilization.
What has been needed is a catheter design incorporating a thinner inner liner with clinically-desirable characteristics. The present invention satisfies these and other needs.